2019 SDN上机第2次作业

1. 利用mininet创建如下拓扑，要求拓扑支持OpenFlow 1.3协议，主机名、交换机名以及端口对应正确，请给出拓扑Mininet执行结果，展示端口连接情况

Python脚本

from mininet.topo import Topo
 
class MyTopo( Topo ):
    "Simple topology example."
 
    def __init__( self ):
        "Create custom topo."
 
        # Initialize topology
        Topo.__init__( self )
        L1 = 2
        L2 = L1 * 3
        s = []
        h = []
          
        for i in range( L1 ):
                sw = self.addSwitch( 's{}'.format( i + 1 ) )
                s.append( sw )
    
        self.addLink(s[0],s[1],4,4)
    
        count = 1
        for sw1 in s:
                for i in range(3):
                	host = self.addHost( 'h{}'.format( count ) )
                	self.addLink( sw1, host,i+1,1 )
                	count += 1
topos = { 'mytopo': ( lambda: MyTopo() ) }

运行以下代码创建拓扑

sudo mn --custom ./fattree.py --topo mytopo --controller=remote,ip=127.0.0.1,port=6653 --switch ovsk,protocols=OpenFlow13

使用net命令查看拓扑

pingall测试主机连通性

2. 直接在Open vSwitch下发流表，用vlan得到下列虚拟网段，请逐条说明所下发的流表含义

h1 -- h4互通
h2 -- h5互通
h3 -- h6互通
其余主机不通
将主机1，2，3进入s1的包打上vlan tag，转发端口4

sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:4
sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:4
sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=3,actions=push_vlan:0x8100,set_field:4098-\>vlan_vid,output:4

将从端口4的包去除vlan tag，并根据tag进行转发

sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=0,actions=pop_vlan,output:1
sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=1,actions=pop_vlan,output:2
sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=2,actions=pop_vlan,output:3

将主机4，5，6进入s2的包打上vlan tag，转发端口4

sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:4
sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:4
sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,in_port=3,actions=push_vlan:0x8100,set_field:4098-\>vlan_vid,output:4

将从端口4的包去除vlan tag，并根据tag进行转发

sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,dl_vlan=0,actions=pop_vlan,output:1
sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,dl_vlan=1,actions=pop_vlan,output:2
sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,dl_vlan=2,actions=pop_vlan,output:3